Throughout most of history, especially in Europe, around 20 is considered adulthood. Betrothals of children among noble families are of course common among nobles and royalty, as were marriages, but actual sexual activity? Not much as recorded before adulthood. As for commoners? Early 20's again is the most common age according to Church records (you know, the people that would have kept records of Births, Deaths and Marriages before formal Civil Registry Offices came about).
Besides, the the whole debate for FFXIV is pointless. It was confirmed at 16 in the Tales of the Calamity journals.
Besides, the the whole debate for FFXIV is pointless. It was confirmed at 16 in the Tales of the Calamity journals.